I have a python script which runs on my local linux machine.
I wanted to add e-mail alerts.

I tried installing
mailutils
sendmail
msmtp
postfix

It should have been an easy setup.
I looked for so many tutorials on how to install. Most of them incomplete, many of them I followed or did not work and/or very very old.

I would like to use sendmail as I have used it extensively in the past.

After installing it, I get this error when I send e-mails:

connect to gmail-smtp-in.l.google.com[2a00:1450:400c:c04::1a]:25: Network is unreachable

After some research this seems to be related to my machine not having Ipv6 configured and yes it seems that it is not configured correctly or at all:

ping6: connect: Network is unreachable

not a problem. I tried using IPv4 9 (at this moment I just want to send an e-mail, I don’t care much about safety or anything as this is just a python script telling me that my external HDD has been synced).

Still no luck.

Can you recommend a tutorial or instructions that work?